Hydrocarbon conversion



Patented Jan. 27, 1942 UNITED STATES PATENT OFFICE 2,271,356 HYDBOCARBONCONVERSION No Drawing.

Application June 29, 1940,

Serial No. 343,170

11 Claims.

This invention relates to improvements in processes utilizing chromiumoxide catalysts. More particularly, the invention relates to improvementin processes for changing the carhon-hydrogen ratio of hydrocarbons.Still more particularly, the invention relates to the dehydrogenation ofgaseous and liquid hydrocarbons for the production or oleflnic andaromatic hydrocarbons.

Chromium oxide has been used extensively as acatalyst in reactionsinvolving organic compounds and particularly in the hydrogenation anddehydrogenation of hydrocarbons. Chromium oxide catalysts prepared in agel form have been used particularly in dehydrogenating reactions.Gel-type chromium oxide catalysts have been produced by the slowprecipitation 01 the gel in a dilute solution of a chromium salt,usually chromium nitrate. by means of hydroxides such as ammoniumhydroxide. Other methods for the production of the chromium oxide gelsinclude formation of a chromium acetate solution, as by the addition 01ammonium acetate or acetic acid to a chromium salt solution. andneutralization oi the acetate solution, as by the addition of ammoniumhydroxide. Th gelatinous precipitate or Jelly obtained by these methodsis washed and dried to form dense granular particles which may beemployed as such as catalytic material.

It is an object of this invention to provide a process utilizing achromium oxide catalyst wherein the reactants are contacted withchromium oxide which is superior in catalytic activity to chromium oxidecatalysts heretofore produced. It is a further object of the inventionto provide a process for th conversion of allphatic hydrocarbons havingat least six carbon atoms per molecule to aromatic hydrocarbons bydehydrogenation and cyclization reactions under conditions whereby asubstantially improved degree of conversion is effected.

The chromium oxide catalyst employed in the process of the invention isprepared by the reduction of chromium trioxide in an aqueous solutionthereof. Reduction is accomplished by means of one or more or a varietyof reducing agents. Preferably a reducing agent is employed which isvolatile, or decomposes to iorm materials which are volatile, atrelatively low temperatures and forms oxidation bY-prducts which arethemselves volatile at relatively low temperatures, such as thelow-boiling alcohols and aldehydes and oxalic acid. Other reagents whichare highly reactive and are removable by other means and which formremovable or in nccuous oxidation products may be used.

Production oi the improved chromium oxide catalyst in its most activeform is effected under conditions whereby substantial reduction 01 the.chromium trioxide is eii'ected. In the reduc tion of chromium trioxidein aqueous solution a primary reduction product may be formed which isunsuitable for catalytic purposes and requires more strenuous conditionsto effect further reduction to the desired degree. For example, in thereduction of chromium trioxide in aqueous solution by means oi ethylalcohol it is found that an intermediate product may be' formed whichmay be chromium chromate. This material may be formed by the reaction ofchromium which has been reduced to the trivalent form with unchangedchromium trioxide. This compound apparently forms a reduction barrierwhich requires a higher reduction potential to convert it to a compoundin which the chromium has a lower valence.

Reduction of chromium trioxide under conditions favoring substantialreduction to the trivalent form results in the formation of a gelatinousprecipitate. It a fairly concentrated solution or the chromium trioxideis employed the precipitate may occupy the volume of the soiu tion as ajelly. The presence or the intermediate compound, which will be referredto as chromium chromate for purposes of identification, in

the precipitate may be detected by a thermal analysis of this material.For example, it after suitable washing and drying of the gel at lowtemperature to produce the granular product the latter is heated slowlyto a temperature ot around 200 C. there occurs an exothermic reactionwhich varies in intensity with the proportion 01' chromium chromatepresent. When the material contains a substantial proportion of chromiumchromate the exothermic reaction is viaorous enough to raise thetemperature of the mass or more in about one minute. This thermal eilectis not to be confused with the glow phenomenon which is noticed in theheating oi chromium oxide gels to temperature in the neighborhood of 500C. A sample or material prepared as described may exhibit both of thesephenomena as the temperature is raised first to approximately 200 C. andthen to about 500 C.

It is desirable to avoid the presence of a large proportion 01' theintermediate chromium chromate in the catalyst since it is i'ound thatthe greatest activity is associated with substantially complete absenceof this material in the catalyst although catalysts may be preparedcontaining certain amounts of the chromium chromate, which may betolerated because the activity or? the catalyst still is substantiallygreater than chromium oxide catalysts employed heretofore.

Where it is found, by thermal analysis of the product, that the reducingconditions are not adequate to effect reduction of the chromium trioxideto the desired degree various means may be employed to increase thedegree of reduction. These include the use or reducing agents of greateractivity, the use or greater amounts of the reducing agent the use or ahigher temperature, qrithe u e cha lenger period of application ofheat'in the presence of the reducing" agent. For example, in thereduction of chromium triciently high for a sufllcient length oi time toreduce substantially all the chromium ehromate.

formed precipitate a gelatinous chromium oxide product. which issubstantially free from chromium chro- 2rolonged heatin'g 'at hightemperature the time j nebessary toeflect substantially "completereduction or the chromium trioxide is not deslrablegnoweverl as this'mayresult in the by the reduction of chromium triox'ld'e to was placedon ahot plate and evaporated to dry- A: Jet-black granular material was thus*"obtained. It should be noted that in this preparation the oxalic acidwas employed in a molechlar ratio to the chromic acid of 1.1 to 1.0. It

wssracnd that the use of this ratio of materials produced a catalystsuperior in activity to those ..-produced by the use of oxalic acid andchromic P acid irr different ratios.

CATALYST D .190 grun e: chromium nitrate.n l

were, dissolved in 500 cc. of water. 33 grams of ammonium acetate weredissolved in 135 cc. of water. .The two solutions were then intimately 7mixed. The combined solution e chews to boiling after which 90 cc. ofconcentrated am- .moni-um. hydroxide diluted with'250co, oi water werequickly added with stirringl A... stron homogeneous Jelly was. formed.This jelly"was cutinto cubes of intermediate size. The cubes were shrunksomewhat by heating at50 to 60 C. for 12 hours. After cooling the cubeswere washedby soaking in. distilled water. which was frequently changed..Aiterfnitrate and ammoniurn salts had been washed jaway the cubes wereagain heated at 50 to 60 C. Ior. 12 hours at which time they weredriedto a hard blackvitreous ;material. 'Before use as a catalystthismaterial lwas heated overnight at3ilufc CATALYSTE. i A chromiumnitrate solution was prepared by thsirthe maximuml W r The' inventionwill be desoribedin morc' etau byirererence'to thepreparation of variouscatalysts'made in accordance with the'present invenunion-anal inaccordance with prior proeesses and to" dehydrogenation operationsemploying such c atalystsrlt will bei understood, however, that thfeinvention is not limited by such specific exaniples-bui;rediroctdd-hroadly to processes utiummon-calmness catalysts: r1 7 In theiurther desQristioKoI-the inventionlrefei ence fwill be asses try-thepreparation and use nfamous chromium no catalysts which :were

* prodiiction of' a catalysthaving an activity less hiifls h-black incolor.

to stand for'two weeks. cc. of ethyl alcohol were again added, and thesolution was warmed on a hot plate for two days until the odor of'acetaldehyde disappeared again.

just water, i "C. overnight a black granular gel-type material g sobranea l ads od -sraduc k l l 160 7 rams or chrornl trioxide were dissolvedH iais -liters of ,wamnevEighf 10 CG. portions f ethyt-alcohol wereadded -with shaking at- 5- l minute intervals.- The preparation becamedark in color, and "considerable heat was werv d; After addition o!- the8th portion of aidoiiol the reaction mixture was allowed to stand r fourhours ai'ter'which 80 cc. of alcohol were added earactly as before. Thereaction mixture A tration and drying at 120 C. the precipitate wasconverted to a granular material which was CATALYST l3 r 40 grams ofchromic acid. CF03, were dissolved 6 in i liters oi distilled water andcc. of ethyl j falcoho1' were added. The solution on standing turneddark in color and evolved acetaldchyde.

The solution was boiled for some time until active 7 evolution ofaldehydes ceased and then was per- Therealter *X darkbrown'pr'ecipitated suspension was obtained which' 'oir filtration setth a brown gel.

*Thiswas washed 'withfstlrring with 2 liters of I Am? filtration anddrying 8t 110 7 7 a portra s-rt) {0 fid' were dissolved. in 250,-;ec. ofwater. anagrams V the course of day. After the reactionha "slowed downthe mixture dissolving 76 grams orchmmmnr nitrate, nonah y'drate, inBliters of water; 'To' thl'ssolution there were added dropwise and withvigorous stirring about 6 liters of 0.l norrnal ammonium hydroxide; Theaddition'of the first half of the ammonium hydroxide to the chromiumnitrate solution was carried out slowly at the rate of about 3 liters in6 hours. Stirring was continued thereafter for about 4 hours to dissolveany precipitate formed. The remainder of the hydroxide was then addedwith" continued stirring. On completion of the addition of the ammoniumhydroxide the precipitate which was formed was allowed to settle and theexcess liquidremd'ved by decantation. The precipitate was then washedseveral times by agitation with fresh water followed by settling anddecantation of the water. Washing was continued to'the point ofincipient peptization of the chromium oxide. The precipitate was thenfiltered and dried at C. for several hours to convert it to the blackrelatively dense granular form. Before use the catalyst thus preparedwas heated gradually to approximately 300 C. and held at thattemperature for about 10 hours. v

CATALYST F V permitted to stand for 12 hours during which of oxalic acidwere j time a still black jelly formed. This precipitate was washed bydecantation withiarge volumes of water. Ten such washings were effectedbeiore incipient peptization of the chromium .oxide indicated thatwashing was complete. The prodnot was then filtered, dried for 15''hours at C .and finally up to 350*0. during =24 hours. The resultingproduetw a black granular .rather hard inate'rialfi CATALYST G 160 gramsoi. chromium trioxide were dissolved in 2000 cc. of water. Eight cc.,portions of ethyl alcohol were added with agitation at theminuteintervals after which the solution was allowed to stand four hours, anequal amount of alcohol then being added in the same manner. Thesolution was then heated on a steam bath under reflux for hours at theend of which time the whole had set to a dark brown almost black gel.The gel was broken up and filtered and the voluminous precipitate wasdried at 100 C. The shining jet-black lumps thus obtained were furtherdried by being heated to a temperature of 300 C. over a period of 4hours and being held at that temperature for 10 hours. Before use thecatalyst was conditioned in an atmosphere of nitrogen by raising it to atemperature of 300 C. in 4 hours, increasing the temperature at the rateof approximately 10 per hour to 400 C., holding the temperature at 400C. for approximately 10 hours and then increasing the temperature at therate of approximately 5 C. per hour to a iinal temperature of 500 C.

CATALYST H Catalyst H was prepared in a manner substan tially identicalwith the method 0! preparation of Catalyst G except that instead ofheating the solution on a steam bath the reaction mixture was boiledvigorously under reflux. During this treatment the catalyst separated inthe form of a dark brown, finely divided precipitate. This was separatedby filtration, washed and dried, a black product being obtained. Beforeuse the catalyst was conditioned in the manner described in connectionwith Catalyst G.

CATALYST H-l Catalyst H-l was prepared in a manner substantiallyidentical with the preparation of Catalyst H except that instead of theconditionmately 40' C. as the material was heated gradually toapproximately 200 C.

CATALYST S A 0.2 N solution (against alkali) of chromium nitrate wasprepared by dissolving 152.4 grams of the nonahydrate in 6 liters ofwater. An ammonia solution of the same normality was prepared bydiluting 7'7 cc. concentrated (29%) aming treatment the dried materialwas placed in a quartz tube and then heated further in a stream ofnitrogen, the heat input being so regulated that the temperatureincreased approximately 1 to 2 C. per minute. Heating in this mannercaused the catalyst to undergo the glow phenomenon at a temperature ofapproximately 500 C., the mass exhibiting a temperature rise ofapproximately 200 C. in about one minute after glowing was initiated.

The glow phenomenon exhibited in the preparation of Catalyst H-l istypical oi! the behavior of chromium oxide gels when heated in thistemperature range, and, as pointed out above, is not to be confused withthe exothermic temperature effect which may be exhibited by a catalyst,prepared in this manner at temperatures around 200 C. Actually, in thedrying of Catalysts H. and H-1 only a slight thermal effect was noticedas the temperature reached approximately 200 C. This indicated that thereducing conditions employed in the preparation 01' these catalysts weresufllciently severe to eilect substantially complete reduction of allchromium chromate formed during the reaction as an intermediat .productwhereby the finished catalyst contained substantially none of thismaterial. In the preparation of Catalyst G, however. reduction was notso complete with the result that the finished catalyst contained anappreciable but tolerable amount of chromium .chromate. This wasindicated by a sudden temperature rise of approximonium hydroxide with 6liters of water. The chromium solution was rapidly stirred and thedilute alkali was added dropwise at a" rate of 6 cc. a minute until 3liters had been used. At this point addition ofalkali was discontinuedand the solution was stirred for 4 hours. following which the additionof alkali at the above rate was resumed. After a permanent precipitatehad formed the remainder of the alkali was added rather rapidly. Due tovariations in the water content of chromium nitrate nonahydrate, more orless than the specified amount of dilute alkali may be required forcomplete precipitation. The amount of nonahydrate specified above isbased on the actual composition of the sample used. The gelatinousprecipitate was allowed to settle and the supernatant liquid was removedas completely as possible, following which sufilcient distilled waterwas added to bring the level up to the previous mark and the suspensionwas stirred for a, half hour, allowed to settle, and the supernatantliquid was again removed. This method of washing was continued until theprecipitate began to peptize, about six changes of water being required.The washed precipitate was sucked as dry as possible on a Biichnerfilter and then transferred to an oven, where it was kept at C. for 24hours. Before use the catalyst was stabilized by bringing it up to 300C. over a course of 5 hours, following which it was maintained at thistemperature {or 10 hours.

Proper specific directions for carrying out reduction of the chromiumtrioxide to obtain the desired product are given in connection with thedescription of the preparation of Catalysts A, B, C, G and H. The properconditions for using other reducing agents and for other concentrationsof the chromium trioxide olution may be determined readily by thoseskilled in the art, it being understood that the reduction should becarried out under conditions suillciently severe to limit the proportionof chromium chromate in the product to a tolerable amount. In followinany method of preparation the presence of large amounts of chromiumchromate in the product may be detected readily by a thermal analysis ofa portion of the product in the manner described above. Where suchthermal analysis results in a substantial exothermic reaction at about200 C., indicating the presence of substantial amounts of chromiumchromate, the procedure may be corrected by increasing the degree 01'severity of the reducing conditions, as described above.

Preferably, the concentration oi the reagents used should be regulatedwhereby the solution, after being heated to promote the reductionreaction and remove volatile by-products, contains at least six grams ofchromium per liter, for example, 40 grams of chromium per liter. Underthese conditions the reduction of the trioxide to the desired degreeconverts the solution to a jelly which may be handled eillciently infurther washing and drying operations.

Catalysts A, B, C, D, E and F were employed in the dehydrogenation ofheptane under con omoas wme'h ivlro substantially uniforms In these testoperfititfiis B addilwm employed as represeatatiyeot the catalyst oi thenew process while Catalfistfi; E and 1' were employcdias'irepresentativeromprlor 'lprocesses employmg chromium; prepared "1:2: (1th mm. W4. :3 il a 7: 0 m the opetsflons' employing :Castamsts A,By, 0,13: E IiiiflIEumfm-muuantities1ot.the catalyst were empioyeciiandeliefltane was therer n over eta M al-E W111811 was substantiallyunifoi'in. i'hereaotion temperatnrmwas maintained aadqfi ac ixzmi ra i 1V- 1 1:"-

"The gas ptoduced in thescloperations contained 88' to9% hydrogenrtheremainder of the gas bemg-prmoipallymethane: Thera'te at gasprod-isetioa wasimieasuredt sam this was" taken as an irlfiiatienoflfhe'frelattve acth'rityent the catalysts. 'I'h activtty otthelcatalystsmis measured also by analyscl oi' flrevllquidiprmets. takenat difiererit :int'stvalssstozntheifiheentent of oleflns (seems)? andaromattcsitoluenel. v

resultsfe! the? operationsjemployina Catalysts=A.=, 1ND,- -E aresetiorth in Table). whseln the mam-mama in terms of relative. voliunesofs'ltquid heptanetpenenflnute. and the when? in or relative volumesiofgas. 1 ifl'flhle I "amass or liquid produced fly: inlmln.

'lysts G. H, H! ands l'or the dehydrogenati oizheptane are set forthinTable II.

amen

passed in the vapor-"form over-the catalysts at a emi ve lw pts qut ivolume 01 mm il p g ss s y t ce w h s acti ms mresws n n i flmats tfl6nd 11" operating mews; was oritinu'ed for a period 0! 5 hours, 7 Duringeach run the product was cooled continuously to separa e qu ds an s sa emense f were collectd and measured. Tneff lig 'd product Iron each 25hours was collected sgarately, and representative samples iwei e F agalyz'ed jfor olefin' and aromatic content.- Rlepresentative samples of thegases produced were iyz d h wfl co t n o hydro en and hydrocarbonsPractically f without exoeptfon the gases produced in these testscontained apbro'ximately 90% hydrogen, the remainder eme M nolt 1)! m he-r 7 V V 0 After" each 5 -hour run'the catalyst employed as reyivlfledby burning from lts surface oar xaace'ous deposits which accumulatedduring the run, operations employing Catalysts G. H andBirjevlyiflcation lwas eflected by oyfer the catai st nitrogen gascontaining 0.5 to 1.0% oxygeaatteniperatures not substantially aboveBGO"'C. In the revivlflcation 0! Catalyst 11-! air was passed over thecatalyst at the reaction temperature.

Theresalts o! the operations employing Oateefas produced indicate theataiiBtB B and C whlch that'of 'fhisisnoerlorltyh indi- V v 4 liquidproducts andpajrttcgxiarii ln 'tiorfirith the percentno an a m products.In em pfthe'lidmd products set is} emfiafisosssagum be based on vestates takenfbt'er' slmlIar periods. aniiiitjfi oftheji'odiict ofcatalyst 2: seem be coaffiirefitotneasalssm a: the prodhe operation 15kmsewmeaml was f jiilysjq" as} set or n P 1 a 1 fsseeameaesw oemms e 7 igawm 'byfiata 5K (335%. V R35; g mes were aiso testod "ta overaslmilarperlomthat h l'aoiell" was can" 03:! st can! a one 7 v o a n1 sRun v 0 r Percent V 2.2.59 Relative volumesofgaspmdueed an 27 1.. 21.09025.500 24,as0 19 2 17.780 22.580 23.420 13.1 a 3" 11.100 10.000 21,42015 4' 10.400 1am 20.130 25.5 r, mesa 18.941077 00.120

- 2-- so: as J 3 $23 5% 1%.? e'new'r ess as exemplifies! 16. mm 11kmls'cso sews and s- :z-s: as

catelcnpiifiml by the 1 7 f 1mm 17.320 moan sentative samples of theliquid products are set 5 forth. The figures in parentheses indicate thenumber of the run from which the sample was taken.

The results summarized in Table II emphasize the superiority of theprocess employing the new catalyst over prior processes, as exemplifiedby the operation employing Catalyst S. Catalyst S was prepared by amethod similar to the method of preparation of Catalyst E. The relativevolumes of gas produced indicate that Catalyst H is was slightlysuperior in activity to Catalyst G while both are substantially superiorto Catalyst S. The difierence in activity between Catalysts G and Hprobably is accounted for by incomplete reduction during the preparationof Catalyst G,

as described above. Catalysts G, H and H-1 exhibited a gradual declinein activity to a stabilized level of activity during repeated runs. Thisdecline in activity, however, is not suiiicient to eliminate the marginof superiority of these catalysts over Catalyst S. Catalyst I-I-l wastested during a series of 47 5-hour operating runs, each followed byrevivification of the catalyst by means of air. The eventualstabilization of the activity of the catalyst is indicated by theaverage gas production during Runs 3.8 to 47, during which runs therelative volume of gas produced exhibited an average deviation ofapproximately 1%. Catalyst H-l was therefore stabilized at a level ofactivity approximately greater than the stabilized activity of CatalystS. This margin of superiority of Catalyst H-I over Catalyst S is basedon the stabilized level of activity or Catalyst H-l. In addition to thismargin of superiority Catalyst I-I-l, during 40 the first 32 runs,exhibited a margin of superiority over the stabilized activity ofCatalyst S varying from approximately 50% to approximately 140%.

The superiority of the process employing Catalysts G, H and H-1 over theprocess employing Catalyst S is further shown by consideration of theanalyses of the liquid products of i these operations as exemplifiedparticularly by the percentages of aromatics in the products.

Analyses of the liquid products collected in the first half of the firstrun on each catalyst indieats a production of aromatics by Catalysts G.H and 1-1-1 01 30 to 200% greater than the production of aromatics inthe operation employing Catalyst S. This superiority is furtheremphasized by consideration of the percentage of arcmatics in the liquidproducts of the last half of later runs. For example, the liquidproducts of the last half of Run 16 on Catalyst H and Run 46 on CatalystH-l contained approximately 4% aromatics whereas the liquid product ofthe last half of a good run on Catalyst S contained less than 1%aromatics.

The foregoing data indicate that the process of the present invention is01 particular advantage in the conversion of aliphatic hydrocarbonscontaining at least six carbon atoms per molecule to aromatichydrocarbons. In carrying out the conversion of aliphatic hydrocarbonsto aromatic hydrocarbons the hydrocarbons are contacted with thecatalyst at temperatures within the range of 300 C. to 600 C.(preferably 450 C. to 550 C.) at a space velocity which, whilesuflicient to effect production of aromatics at a substantial rate, issufilciently low to produce a substantial proportion of aromatics in theliquid product. In the temperature range mentioned the rate ofconversion of aliphatic hydrocarbons to aromatic hydrocarbons variesinversely to the space velocity and directly with the temperature. Atlow temperatures within this range, therefore, a low space velocityshould'be employed while at higher temperatures a higher space velocitymay be used although these factors are governed also by the character ofthe material treated and the nature or the product desired. In general,the space velocities employed in this temperature range will fall withinthe range of 0.1 to 3 volumes of aliphatic hydrocarbons (liquid basis)per volume of catalyst space per hour. The most advantageous spacevelocities will be found in the range of 1 to 2 volumes of liquid pervolume of catalyst per hour.

The new process is particularly useful in the treatment of gasolinemotor fuel to improve its anti-knock qualities. As an example of thisapplication of the process there is set forth in Table III the resultsof the treatment of an East Texas virgin naphtha by contact at varioustemperatures with Catalyst 1-1-1. The naphtha approximated commercialgasoline in boiling characteristics having initial and end boilingpoints of 32 C. and 202 C., respectively, and a Reid vapor pressure of5.1 pounds per square inch. In preparation for all but one of theoperations referred to the naphtha was fractionated to separate thelower boiling portion thereof and leave a topped naphtha, consisting ofabout of the total naphtha, having initial and final boiling points of98 C. and 211 C., respectively. After dehydrogenation of the toppednaphtha it was blended with the low-boiling constituents, previouslyseparated by fractionation, in order to reconstitute the total naphtha.

Table III Dehydrogemtion of t pp d East Texas virgin naphtha C. E. R.octane Percent nm at Temp. Feed 8 Hours Total hydro- V Y 388 gen Toliped Total nap tha naphtha 415 0. Taped naphan a a, use a9. 0 ems mom.a 0.50 5 13,830 an 58.0 01.2 somer 0.50 2 am an 59.0 63.2 500 o 0. 2s a11,502: as 2 as. 7 65.0 500 0 Total naphtha. 0. 25 5 m, sea as. s as. s500 o Togped naph- 0.15 a a, can 84. a s1. 7 ea 2 525 0. do 1.00 1522,790 84. a 00.0 can also. a p 1.00 1 e020 sea 61.9 eats Feed... 47. 45e. 7

fr i-obi i flrij pse won ts worth. flftheiidsixtiiigroiiosnresuitableion this terms" v or ll qliid iedjr hearse?purpose, volume ore me-s ace} est produetioni's 'giv- These who; V otheridiom es t erlfiig'gs"offfreln tiveiiioin'mes of gas produced accruingin the iiractiee or theinventiom will be?- dnrlnfthe runrwhoseduratlonds indicated in 5 apparent !rom n;cons1deration o! theioregoing,

the column under "Hours! 'riiepercefitege or" description snd reierenoeto the results of the hydrogen intfief'g'as lsalso indicated. runspractical applicn'tion of the processreltiis to'be veriedin length fromito'h hours, Betweenruns understood, however, that this invention is'nothe; oo lv 'tj irevlvifled'by treatment wlth oir llmitedhy suchrererlente to speoiflc operations tLWw m'W -t r "1 The resetivmsv'olvediif the treatment of'the plieations other than thosespecifically; described.

but is or broader QBOBGPBDIKLS suseoeptiblerot or n'sfihtha'werefiirlnidrliidehydrogenation reac- "This application isncontinnatlon-inopmrt of tiofis, esshowniby the tsict'that the gasproduced our prior spplication serinl No. 181,598,1i1ed-Deat tne nighesttemperstnre contained 85% 117 cember 24, 1937, now Patent Ni:2,211,302,dated 1 drogen. mi mu yieldbbtsined in tliemnst Angust'13,1940.

'uhspace velooitiwasfoger 88%Dyvolume. We claim:

trestment'with sir stthereection temperature V V hydrogenation ofhydroea 'rlion gsses. As an exwhich comprises contactingsaidrhydroearbons at amp eo th a l on [H e or o 'ref r no elevatedtemperature wimsootoiysu oommsmg is r'n'ede to theresuitsfot employing'c' gem ehromium oxide repared-by a NK Pi d n m n e $171115! chromiumtrloxide undo; reducing agent in aquep epar ion otcatelys G w h w s, ted to ads solution to romi n 'gelatinous reduction prodsulojeot it tolhfii mii. in the manuct'and drying said gelatinous product; nerdescribed in with t P p 2. Aprocess ror convertinn aliphaflo; hydrooarr(lil l y t 3-1, Thiflontnbst me?! be designated 5 bons'to aromatichydrocarbons which comprises o identification as C a r In thesercontacting aliphatic hydrocarbons hnvinget least stations u T w s i toContact with 6 carbon atoms per molecule at eievated tem- Cete rstwi gtvarious te p s d a perature with a-oatalyst comprising Eel-type 95 l i ew he results which are Set chromiuni oxide prepared by reaotins chromiumiorth' in'l'eblfIV, N f. 3 trioxide snd'a'reducinaagentinsqueoussoiuflon V toiorrn a'gelstinous reduction produetanddryinz1 said gelatinous products r r 3. A prooess'ior changing thecarbon-lwdroeen on 5?? Fa s??? 1 ratio ot-hydrooarbons which comprisescontactvelocity V ins ssidhydrocerbons at eteveted temperature r V nim.rm.- mm. remiss; withncatalystoomprisilixgel-type chmmhimox-' Q J l ideprepared by reacting chromium trloxide'and 2%--.. jr g g E2 j a reducinges'engin sqgideocutsalidution to iorm s gelatinous reduc onipr u dmg'said' 3e M :11 12.0 m 121' as o latmaus Fromm 7 4. A processior'promoting reactions or organomfi smaozsezess zsiss 16 m M mswwblemhemmc or temperature. and mm per volume at a eifeot ofenaotive'chromium oxide cotaiystwhioh In: space per hour. The "mus am mconiprlses contacting said orsanie materials at in terms otper'oentoleflns in the product during W? a thenrst hour and during the inn5-hour gejtype N w? m Between 11ml Catalyst 0-1 was revivifled liy 7mmmfimfldemfl "m one solution to form a geiatinousreduction prod not anddrying said geietinousproduct;

The process is also a vantageous tor the de- I 13A process for dehydrogenstins The operations whose resuitssre set forthr m5 5. Apt forhmfmgwmmrmambo;

mo ffi fiififi ofe "@2333. we m o m ms nowm e oxide catalyst prepared byreduction 0! ehro- WM with n er? 99'? 18mg mium trioxldein aqueoussolution. These edcmomiumwde W y m vreside prineipallr in we toot thatin we d o PM E me! @1 1 in will 5 7 7 tion it is ossible W fil fit l'tii mm o to obtain a decree or which is zreater 31%;!!! RFP QFF PQ 3* wP than tsinedin not i proee e: ger t ir ig fi de the some zzon- AProcess e y s n ine hydrocarbons ditions ofitemperature, pressure, specevel it which comprises oontwtlns said hydro arbons at m ifrmifimwdefillifib'; i'fimfifimi um 7 operatic roved c chr nti u m onde ci t ly t fiig e em giy g m the ""trioxide and a reduoins agent therefor inaqueous ionn ems oxide as such, or the latter solution under conditionssuitable to effect the be m m cmmffiiuonmmmer mar, r duction of agelatinous chromium oxide re- :1! g v fg as mm or we chmmmm ductionproduct substantially tree or chromium ggr mpomng materials may bemchromste and drying said gelatinous product.

A w m 'gte to the catalytic efr 7; A process for dehydrogenatinzhydrocarbons whichnomprises contacting said hydrocarbons st elevgtegtemperature with a catalyst comprising chronnum oxide prepared byboiling an aqueous solution of chromium trixode and ethyl alcohol toefleet the production oi a gelatinous chromium motto or iessef aesreethan the ohrw sing; rsrticulsrlwsmteble for such supv are Dfjfi metalsof "cm-om din ones m o in I mi m a m t riels 'ozrideo reduction productsubstantially tree of or; 15-51 rofiote the V chromium chi-ornate anddrying said gelatinous 8. A process, for improving the anti-knock valueoi gasoline which comprises contacting at least a fraction of saidgasoline at elevated temperature with a catalyst comprising chromiumoxide prepared by reacting chromium trioxide and a reducing agent inaqueous solution to form a gelatinous chromium oxide reduction productand drying said gelatinous product.

9. A process for dehydrogenating normally gaseous hydrocarbons whichcomprises contacting said normally gaseous hydrocarbons at elevatedtemperature with a chromium oxide catalyst comprising chromium oxideprepared by reacting chromium trioxide and a reducing agent in aqueoussolution to iorm a gelatinous chromium oxide reduction product anddrying said gelatinous product. i

10. A process for dehydrogenating hydrocarbons which comprisescontacting said hydrocarbons at elevated temperature with a catalystcomprising chromium oxide prepared by reacting chromium trioxide andoxalic acid in aqueous so-v lution in the molecular ratio ofapproximately 1.1 molecules of oxalic acid to 1 molecule of chromiumtrioxide to effect production of a gelatinous reduction product anddrying said gelatinous product.

11. A process for dehydrogenating aliphatic hydrocarbons which comprisescontacting said hydrocarbons at elevated temperature with acatprecipitate.

' JOHN TURKEVICH.

ROBERT F. RU'I'HRUFF.

